The threat of fuel shortages along with increased energy costs and environmental concerns, have created a need for alternative energy sources, particularly those that are renewable. Biofuels have become a popular alternative fuel source because they are renewable. Crops such as corn have been considered for producing biofuels because they are capable of being converted to alcohol. When ethanol is made from corn, it arguably takes more energy to produce the ethanol than is actually obtained from it. Also, using a grain such as corn for fuel precludes it from being used as food for humans. Corn production is also hard on the land because it erodes the soil. However, a biomass such as algae is capable of creating a fuel with a high power density, is renewable and, unlike corn, does not take away a food source from humans and livestock.